detecting-evasion-techniques-in-endpoint-logs

Detects defense evasion techniques used by adversaries in endpoint logs including log tampering, timestomping, process injection, and security tool disabling. Use when investigating suspicious endpoint behavior, building detection rules for evasion tactics, or conducting threat hunting for stealthy adversary activity. Activates for requests involving evasion detection, defense evasion analysis, log tampering detection, or MITRE ATT&CK TA0005.

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リポジトリ: mukul975/Anthropic-Cybersecurity-Skills
ソースの最終更新活動: 2026年6月1日 10:13
検出された SKILL.md の言語: 英語
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フォーク: 3,366

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name	detecting-evasion-techniques-in-endpoint-logs
description	Detects defense evasion techniques used by adversaries in endpoint logs including log tampering, timestomping, process injection, and security tool disabling. Use when investigating suspicious endpoint behavior, building detection rules for evasion tactics, or conducting threat hunting for stealthy adversary activity. Activates for requests involving evasion detection, defense evasion analysis, log tampering detection, or MITRE ATT&CK TA0005.
domain	cybersecurity
subdomain	endpoint-security
tags	["endpoint","edr","threat-hunting","defense-evasion","MITRE-ATT&CK","detection-engineering"]
version	1.0.0
author	mahipal
license	Apache-2.0
d3fend_techniques	["File Metadata Consistency Validation","Content Format Conversion","File Content Analysis","Platform Hardening","File Format Verification"]
nist_csf	["PR.PS-01","PR.PS-02","DE.CM-01","PR.IR-01"]
mitre_attack	["T1055","T1547","T1059","T1036","T1027"]

Detecting Evasion Techniques in Endpoint Logs

When to Use

Use this skill when:

Hunting for adversary defense evasion techniques (MITRE ATT&CK TA0005) in endpoint telemetry
Building detection rules for common evasion methods (process injection, timestomping, log clearing)
Investigating incidents where adversaries disabled or bypassed security tools
Analyzing endpoint logs for indicators of living-off-the-land binary (LOLBin) abuse

Do not use this skill for network-level evasion (use network traffic analysis) or for malware reverse engineering.

Prerequisites

Sysmon installed and configured with comprehensive logging rules (SwiftOnSecurity or Olaf Hartong config)
Windows Security Event Log with advanced audit policy enabled
EDR telemetry (CrowdStrike, SentinelOne, Microsoft Defender for Endpoint)
SIEM platform for log correlation (Splunk, Elastic, Sentinel)
MITRE ATT&CK Enterprise matrix for technique reference

Workflow

Step 1: Detect Log Tampering (T1070)

Windows Event Log clearing (T1070.001):

# Sysmon Event ID 1 (Process Create) for wevtutil
EventID: 1
CommandLine contains: "wevtutil cl" OR "wevtutil clear-log"

# Security Event ID 1102 - Audit log was cleared
EventID: 1102
Source: Microsoft-Windows-Eventlog

# System Event ID 104 - Event log was cleared
EventID: 104

# PowerShell log clearing
EventID: 1 (Sysmon)
CommandLine contains: "Clear-EventLog" OR "Remove-EventLog"

# Splunk query:
index=windows (EventCode=1102 OR EventCode=104)
  OR (EventCode=1 CommandLine="*wevtutil*cl*")
  OR (EventCode=1 CommandLine="*Clear-EventLog*")
| table _time host user CommandLine EventCode

Timestomping (T1070.006):

# Sysmon Event ID 2 - File creation time changed
EventID: 2
# Look for creation times set far in the past on recently-written files
# Correlate with Event ID 11 (FileCreate) - if FileCreate is recent but
# creation time in Event ID 2 is old, timestomping is likely

# MDE Advanced Hunting (KQL):
DeviceFileEvents
| where ActionType == "FileTimestampModified"
| where Timestamp > ago(7d)
| extend TimeDiff = datetime_diff('day', Timestamp, ReportedFileCreationTime)
| where TimeDiff > 30
| project Timestamp, DeviceName, FileName, FolderPath,
    ReportedFileCreationTime, InitiatingProcessFileName

Step 2: Detect Process Injection (T1055)

# Sysmon Event ID 8 - CreateRemoteThread
EventID: 8
# Alert when source process is unusual (not system processes)
# Filter out known legitimate: antivirus, debugging tools
SourceImage NOT IN ("C:\Windows\System32\csrss.exe",
                     "C:\Windows\System32\lsass.exe")

# Sysmon Event ID 10 - ProcessAccess with suspicious access masks
EventID: 10
GrantedAccess contains: "0x1F0FFF" OR "0x1FFFFF" OR "0x001F0FFF"
# PROCESS_ALL_ACCESS = 0x1F0FFF (common in injection)
# Filter legitimate: AV accessing all processes

# Sysmon Event ID 25 - Process Tampering
EventID: 25
Type: "Image is replaced"  # Process hollowing indicator

# Splunk detection:
index=sysmon EventCode=8
| where NOT match(SourceImage, "(?i)(csrss|svchost|MsMpEng|defender)")
| stats count by SourceImage TargetImage host
| where count < 5
| sort - count

# Service stopped events for security services
EventID: 7045 (new service) OR 7036 (service state change)
ServiceName IN ("WinDefend", "Sense", "CrowdStrike Falcon Sensor",
                 "SentinelAgent", "csagent", "MBAMService")

# Sysmon Event ID 1 - Processes that disable Defender
CommandLine contains: "Set-MpPreference -DisableRealtimeMonitoring"
  OR "sc stop WinDefend"
  OR "sc config WinDefend start= disabled"
  OR "net stop" AND ("windefend" OR "sense" OR "csagent")

# Registry modification to disable security features
# Sysmon Event ID 13 - Registry value set
TargetObject contains: "DisableAntiSpyware"
  OR "DisableRealtimeMonitoring"
  OR "DisableBehaviorMonitoring"
Details: "DWORD (0x00000001)"

# MDE KQL:
DeviceRegistryEvents
| where RegistryValueName in ("DisableAntiSpyware", "DisableRealtimeMonitoring")
| where RegistryValueData == "1"
| project Timestamp, DeviceName, RegistryKey, InitiatingProcessFileName

# Sysmon Event ID 1 - Process with legitimate name from unusual path
EventID: 1
Image contains: "svchost.exe" AND Image NOT starts with: "C:\Windows\System32\"
Image contains: "csrss.exe" AND Image NOT starts with: "C:\Windows\System32\"
Image contains: "lsass.exe" AND Image NOT starts with: "C:\Windows\System32\"

# Process name mismatch (original filename vs. current name)
# Sysmon captures OriginalFileName from PE header
EventID: 1
OriginalFileName != (parsed filename from Image path)

# Double extension files
EventID: 11 (FileCreate)
TargetFilename matches: "*\.pdf\.exe" OR "*\.doc\.exe" OR "*\.jpg\.exe"

# Splunk:
index=sysmon EventCode=1
| eval process_name=mvindex(split(Image,"\\"),-1)
| where (process_name="svchost.exe" AND NOT match(Image,"(?i)C:\\\\Windows\\\\System32"))
  OR (process_name="csrss.exe" AND NOT match(Image,"(?i)C:\\\\Windows\\\\System32"))
| table _time host Image ParentImage CommandLine User

# Common LOLBin abuse patterns:

# mshta.exe executing remote content
EventID: 1
Image ends with: "mshta.exe"
CommandLine contains: "http" OR "javascript:" OR "vbscript:"

# certutil.exe downloading files
EventID: 1
Image ends with: "certutil.exe"
CommandLine contains: "-urlcache" OR "-decode" OR "-encode"

# regsvr32.exe executing scriptlets
EventID: 1
Image ends with: "regsvr32.exe"
CommandLine contains: "/s /n /u /i:" OR "scrobj.dll"

# rundll32.exe with unusual DLLs
EventID: 1
Image ends with: "rundll32.exe"
CommandLine contains: "javascript:" OR ".js" OR "http:"

# MSBuild executing inline tasks
EventID: 1
Image contains: "MSBuild.exe"
CommandLine NOT contains: ".sln" AND NOT contains: ".csproj"

# Combine multiple weak signals into high-confidence detection:

# Rule: Potential post-exploitation evasion chain
# Trigger when 3+ evasion techniques observed on same host within 1 hour

# Splunk correlation search:
index=sysmon host=*
| eval technique=case(
    EventCode=2, "timestomping",
    EventCode=8 AND NOT match(SourceImage,"csrss|svchost"), "process_injection",
    EventCode=1 AND match(CommandLine,"(?i)wevtutil.*cl"), "log_clearing",
    EventCode=13 AND match(TargetObject,"DisableRealtimeMonitoring"), "security_disable",
    EventCode=1 AND match(CommandLine,"(?i)(mshta|certutil.*urlcache|regsvr32.*/s.*/n)"), "lolbin_abuse",
    true(), NULL
)
| where isnotnull(technique)
| bin _time span=1h
| stats dc(technique) as technique_count values(technique) as techniques by host _time
| where technique_count >= 3
| sort - technique_count

Term	Definition
Defense Evasion (TA0005)	MITRE ATT&CK tactic where adversaries attempt to avoid detection during operations
Process Injection (T1055)	Technique of injecting code into another process's memory space to execute in a trusted context
Timestomping (T1070.006)	Modifying file timestamps to make malicious files appear old and blend with legitimate files
Masquerading (T1036)	Naming malicious files or processes to match legitimate system files to avoid detection
LOLBin	Living Off the Land Binary; legitimate Windows tool repurposed by adversaries
Indicator Removal (T1070)	Clearing logs, deleting files, or modifying artifacts to remove evidence of compromise